US4323971A - Adjustment means for stretch reduction rolling mills - Google Patents

Adjustment means for stretch reduction rolling mills Download PDF

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Publication number
US4323971A
US4323971A US06/102,411 US10241179A US4323971A US 4323971 A US4323971 A US 4323971A US 10241179 A US10241179 A US 10241179A US 4323971 A US4323971 A US 4323971A
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Prior art keywords
tube
measuring
theoretical
wall thickness
rolling mill
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Expired - Lifetime
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US06/102,411
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English (en)
Inventor
Hermann Moltner
Wolfgang Siebenborn
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Kocks Technik GmbH and Co KG
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Kocks Technik GmbH and Co KG
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B17/00—Tube-rolling by rollers of which the axes are arranged essentially perpendicular to the axis of the work, e.g. "axial" tube-rolling
    • B21B17/14—Tube-rolling by rollers of which the axes are arranged essentially perpendicular to the axis of the work, e.g. "axial" tube-rolling without mandrel, e.g. stretch-reducing mills
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
    • B21B37/78—Control of tube rolling

Definitions

  • This invention relates to adjustment means for stretch reduction rolling mills and particularly to an adjustment device for regulating the total degree of drawing of a stretch reduction rolling mill.
  • Stretch reduction rolling mills are frequently used for the production of tubes for use in a variety of purposes. In general, it is desired that such tubes be produced with a uniform or constant external diameter and a uniform or constant wall thickness.
  • the variation in tube wall thickness in a stretch-reduction rolling mill is essentially dependent on the tractive force that acts in the tube in the longitudinal direction during the diameter reduction. If the tube is reduced without a tractive force, the wall thickness increases during a diameter reduction. If the roll r.p.m.'s are varied such that a tractive force acts on the tube between the roll stands, with a constant diameter reduction and increasing tractive force the wall thickness increase is first reduced, then the wall thickness remains the same, and finally it decreases with a correspondingly high tensile stress on the tube.
  • a precisely regulated total traction and total degree of drawing of the rolling mill are primarily necessary.
  • the tubes entering into the stretch-reduction rolling mill are mutually identical in their diameter and wall thickness and also identical over their length, a quite specific total degree of drawing can be calculated, which needs only to be adjusted and maintained with the necessary precision, in order to obtain finished tubes with a constant external diameter and a constant wall thickness of the desired size.
  • the entering tubes do not meet these requirements; therefore, an attempt is made to equalize the diameter, but primarily to control the wall thickness deviations of the entering tube in the stretch-reduction rolling mill. While a constant external diameter of the tube can be relatively easily obtained with the roll designing, the wall thickness must be maintained constant by appropriate variation of the total degree of drawing.
  • an adjustment device is required for regulating the total degree of drawing.
  • the present invention concerns such an adjustment device for regulating the total degree of drawing of a multi-stand stretch-reduction rolling mill for the reduction of tubes, with which the degree of drawing can be adjusted as a function of the entrance measurements of the mean wall thicknesses of the tube in order to obtain the desired constant finished tube wall thickness.
  • the familiar adjustment device does take into account the fact that the entering tubes have nonuniform wall thicknesses because it operates as a function of the entrance measurements of the mean wall thicknesses of the tube.
  • the familiar adjustment device lacks the reverse control over the outcome of an adjustment of the total degree of drawing and the possibility of a renewed correction of the adjustment after this reverse control.
  • a continuous regulation of the total degree of drawing takes place in this familiar adjustment device and it thus happens that the tube sections are affected by a regulation step for which it was not intended.
  • the purpose of the present invention is to improve the familiar adjustment device so that the adjusted total degree of drawing is more precisely adapted to the individual tube sections as they enter the stretch-reduction rolling mill.
  • a digital unit which calculates the theoretical stretchings from the wall thicknesses and external diameters of both the actually entering and also the desired finished tube section intermittently and the actual stretchings from the entrance and exit speeds of the tube continuously, and that a regulator that adjusts the r.p.m.'s of the rolls as a function of the differences in the theoretical and actual stretchings is present in a control loop.
  • the digital unit determines the theoretical stretchings from the quotients of first-pass cross section and finished cross section, which result from the corresponding wall thickness and diameter of the tube.
  • the theoretical stretching is thus obtained as follows:
  • S o is the first-pass wall thickness
  • S is the finished wall thickness
  • D o the first-pass diameter
  • D the finished diameter
  • ⁇ theor .
  • the theoretical stretching Because the finished wall thickness S and the finished diameter D are precise desired values, they are not measured, but fed directly to the computer.
  • the first-pass wall thickness, which frequently fluctuates, is measured on the entrance side in front of the first roll stand.
  • the first-pass diameter D o can also be fed in as a fixed value if it is determined with certainty that the diameter of the entering tube fluctuates only very slightly and is essentially constant, which is the case in practice, e.g., with superposed tube welding installations with calibrating stands. However, if there is the danger that the first-pass diameters fluctuate, it is recommended that they be measured on the entrance side.
  • the measurement values are fed to the digital unit, which calculates the theoretical stretching ⁇ theor . from them, together with the values fed in.
  • the actual stretching ⁇ act . is also determined by the computer, i.e., measured from the entrance speed V o by a speed-measuring device in front of the first roll stand and the exit speed V measured by a speed-measuring device beyond the last roll stand.
  • the actual stretching ⁇ act . is obtained from the quotient of the two values.
  • the difference ⁇ is deduced from the theoretical and actual stretchings and the total degree of drawing is modified in accordance with the magnitude of this difference through the roll r.p.m.'s such that a compensation between theoretical and actual stretching is effected.
  • the computer and measuring devices used in this connection are familiar in themselves.
  • the mean wall thicknesses of the successive tube sections can be measured with the wall thickness measuring device on the entrance side.
  • the lengths of these sections correspond to the tube volume in the controlled system of the rolling mill, which extends from the first to the last of the passes, between which the tube is loaded with the full traction in the stationary operating state, and the intermittent theoretical stretchings are determined, using this mean wall thickness for such a tube section.
  • a theoretical stretching of a tube section is the guide value of the regulator in the control loop from then on, if the middle of this tube section has reached the controlled zone, i.e., the first pass, between which the tube is loaded with the full traction in the stationary operating state.
  • Each theoretical stretching determined is accordingly the guide value of the regulator until the theoretical stretching of the subsequent tube section replaces it in an identical manner, that is, the middle of the subsequent tube section has reached the beginning of the control zone.
  • the stretching in the middle of such a tube section is accordingly guided during passage through the control zone of the rolling mill by only a single, constant theoretical value, which is calculated in accordance with the mean value of the wall thicknesses of this tube section measured on the entrance side.
  • the theoretical stretching of a tube section is used with a time delay as the guide value of the regulator, namely, at a point in time when half of the tube section has already entered into the control zone.
  • both the entrance and exit speeds of the tube are required.
  • An actual stretching can thus be calculated only if both speed-measuring devices are in operation, i.e., the stationary operating state is prevailing.
  • non-stationary operating states i.e., when the beginnings of the tubes are entering and the tube ends are emerging, no actual stretching can be determined for a substantial tube section, because either the speed-measuring device on the exit side or the one on the entrance side furnishes no values because the tube is still absent there.
  • the regulator setting determined last be stored and continue to be used.
  • a control system with a control computer is assigned to the regulator and the control loop, with which the dependence of the actual regulator settings on the measured initial wall thicknesses and possibly also the initial diameters can be calculated and stored during operation of the control loop in the stationary operating state, and that the roll r.p.m.'s and thus the total degree of drawing can be controlled with the control system on the basis of the stored data from the control computer in the case of an interrupted control loop in the nonstationary operating state.
  • the control computer thus operates in the stationary operating state and calculates from the r.p.m. and/or total drawing degree settings of the regulator the dependence of these settings on the values measured on the entrance side.
  • the control computer thus learns and stores this dependence and arrives at a control law. According to this control law, the rolling mill is controlled during the period in which the control loop is interrupted, even though one of the speed-measuring devices no longer furnishes any data and therefore no actual stretching values based on measurements are available.
  • FIG. 1 shows a stretch-reduction rolling mill with the arrangement of measuring devices for the adjustment arrangement according to the invention
  • FIG. 2 shows a symbolic presentation of the processing of the measurement and feed values
  • FIG. 3 shows the control loop according to FIG. 2 with an additional control system.
  • the roll stands of a stretch-reduction rolling mill are designated in FIG. 1 by 1-12, into which a tube 13 has entered.
  • the tube 13 moves in the arrow direction X through the stretch-reduction rolling mill, which can have a completely different number of roll stands.
  • a wall thickness measuring device 14 is provided on the entrance side; for example, it can consist of an isotope radiation meter. This measures the wall thickness S o of the tube 13 upon entrance.
  • a speed-measuring device 15 which can consist of a measuring wheel that is connected to an impulse transmitter, measures the entrance speed V o of the tube 13.
  • the external diameter D o of the tube 13 can also be measured at the entrance side. In many cases, however, it is sufficient to feed this external diameter D o in as a fixed value.
  • the external diameter D and the wall thickness S of tube 13 on the emergence side are also fed in as fixed values. Therefore, these three values are represented in FIG. 1 only with arrows. It is obvious that these values should also be modified in the case of changes in the rolling program.
  • the exit speed V is measured with a speed-measuring device 16, which can be designed identically as the speed-measuring device 15.
  • the measurement and feed values S, D, S o and D o which are determined or fed in on the entrance and exit sides accordingly to FIG. 1, are shown on the left in FIG. 2.
  • the dark arrow symbolizes that a feed value is involved, while the light arrow designates the continuous measurement value. Because the external diameter of the entering tube can be either measured or fed in, its symbol D o is given in both boxes in parentheses.
  • the measurement and feed values S, D, S o and D o are transmitted to the digital unit shown on the right, which determines the theoretical stretching ⁇ theor . from them.
  • the digital unit determines the actual stretching ⁇ act . from the measured speed values V o and V.
  • the control loop is shown in the right-hand portion of FIG. 2, which shows how the two stretching values ⁇ theor . and ⁇ act . are compared with each other and the differences ⁇ in the two are conveyed to the regulator. From the stretching difference ⁇ the regulator determines the r.p.m. difference ⁇ n that is necessary in order to match the actual stretching ⁇ act . to the theoretical stretching ⁇ theor .. The r.p.m.
  • control loop As in FIG. 2 the same control loop as in FIG. 2 is involved. It is designated by thick solid lines. The other symbols (not shown) for the measurement and feed values S, D, S o and D o as well as those for the digital unit are the same as in FIG. 2.
  • a control system which is assigned to the control loop, is also shown in FIG. 3 with thinner solid lines. This control system is required only because of the nonstationary operating state, in which the values measured on the entrance or exit side temporarily drop out.
  • the control system has a control computer which receives the drive r.p.m. n z of the auxiliary drive and, during stationary operating conditions, also the theoretical stretching ⁇ theor ..
  • control computer determines the dependence of the auxiliary r.p.m.'s n z on the theoretical stretchings ⁇ theor . during the stationary operating state, from which a control law results for the computer which it continuously checks and possibly modifies. This takes place until the stationary operating state ends and the control loop is interrupted due to the lack of measurement values.
  • a control unit functions in accordance with the information of the control law that the control computer determined during the stationary operating state.
  • the control unit feeds the r.p.m.'s n z determined on the basis of the control law in the control computer into the drive of the rolling mill during the nonstationary operating state or as long as the control loop is interrupted.
  • the control computer thus functions only when the control loop is closed, while the control unit functions only when the control loop is interrupted or open.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Control Of Metal Rolling (AREA)
US06/102,411 1979-11-23 1979-12-11 Adjustment means for stretch reduction rolling mills Expired - Lifetime US4323971A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE2947233A DE2947233C2 (de) 1979-11-23 1979-11-23 Vorrichtung zur Steuerung der Wanddicke von Rohren
DE2947233 1979-11-27

Publications (1)

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US4323971A true US4323971A (en) 1982-04-06

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US06/102,411 Expired - Lifetime US4323971A (en) 1979-11-23 1979-12-11 Adjustment means for stretch reduction rolling mills

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Country Link
US (1) US4323971A (enrdf_load_stackoverflow)
JP (1) JPS5674309A (enrdf_load_stackoverflow)
AT (1) AT363433B (enrdf_load_stackoverflow)
CS (1) CS229637B2 (enrdf_load_stackoverflow)
DE (1) DE2947233C2 (enrdf_load_stackoverflow)
ES (1) ES486860A1 (enrdf_load_stackoverflow)
FR (1) FR2469963B1 (enrdf_load_stackoverflow)
GB (1) GB2070806B (enrdf_load_stackoverflow)
HU (1) HU182228B (enrdf_load_stackoverflow)
IT (1) IT1148248B (enrdf_load_stackoverflow)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4415976A (en) * 1981-04-28 1983-11-15 Westinghouse Electric Corp. Method and apparatus for automatic mill zero correction for strip width
US4557126A (en) * 1981-09-30 1985-12-10 Mitsubishi Denki Kabushiki Kaisha Control device for continuous rolling machine
US5086399A (en) * 1988-09-20 1992-02-04 Kabushiki Kaisha Toshiba Method and apparatus for setting-up rolling mill roll gaps
US5485386A (en) * 1990-12-12 1996-01-16 Andreasson; Bengt Method and device for the control and regulation of the stretch of a running web
US20200391263A1 (en) * 2017-11-21 2020-12-17 Sms Group Gmbh Device for controlling a stretch-reducing mill
CN112823064A (zh) * 2018-10-11 2021-05-18 Sms集团有限公司 管件张力减径时的壁厚控制
US11745235B2 (en) 2018-08-20 2023-09-05 Sms Group Gmbh Method and device for controlling a stretch reducing rolling mill for wall thickness compensation

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3028210C2 (de) * 1980-07-25 1990-12-06 Kocks Technik Gmbh & Co, 4010 Hilden Walzstraße zum Streckreduzieren von Rohren
US4558576A (en) * 1983-11-14 1985-12-17 Morgan Construction Company Automatic gauge control system for multi-stand tied block rod rolling mill
DE3533120A1 (de) * 1985-09-17 1987-03-19 Kocks Technik Walzstrasse zum walzen von rohr- oder stabfoermigem gut
DE3643659A1 (de) * 1986-12-18 1988-07-07 Mannesmann Ag Verfahren zur steuerung der rohrwanddicke
DE3819571A1 (de) * 1988-06-06 1989-12-07 Mannesmann Ag Verfahren zur regelung der wanddicke beim streckreduzieren von rohren
DE4243688C1 (de) * 1992-12-18 1994-03-31 Mannesmann Ag Verfahren und Vorrichtung zum Ausrichten einer Luppe vor dem Streckreduzierwalzwerk
DE102012020444B4 (de) * 2012-10-18 2015-01-22 Vdeh-Betriebsforschungsinstitut Gmbh Verfahren zur Ermittlung der Zugfestigkeit eines Bandes in einer Richtmaschine und Zugfestigkeits-Softsensor

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3074300A (en) * 1959-04-20 1963-01-22 Beloit Iron Works Automatic control and drive for mills
US3766761A (en) * 1971-10-07 1973-10-23 Wean United Inc Rolling mill control
US3874211A (en) * 1973-03-02 1975-04-01 Sumitomo Metal Ind Method of controlling the wall thickness within a tube elongater by utilizing a screw down control
US4002048A (en) * 1975-12-19 1977-01-11 Aetna-Standard Engineering Company Method of stretch reducing of tubular stock
US4086800A (en) * 1973-09-24 1978-05-02 Friedrich Kocks Gmbh & Co. Process and rolling mill for stretch reduction of tubes

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE535052A (enrdf_load_stackoverflow) * 1954-01-26
DE1427922C3 (de) * 1965-04-07 1975-08-14 Fa. Friedrich Kocks, 4000 Duesseldorf Verstelleinrichtung zum Regeln des Gesamtstreckgrades beim Streckreduzieren von Rohren
US3496745A (en) * 1967-05-01 1970-02-24 Kocks Gmbh Friedrich Process for stretch-reducing tubes
DE2441493A1 (de) * 1974-08-29 1976-03-18 Mannesmann Roehren Werke Ag Verfahren zum auswalzen von rohren in einem streckreduzierwalzwerk
DE2450224A1 (de) * 1974-10-23 1976-05-06 Kocks Gmbh Friedrich Verfahren zur veraenderung der wanddickenaenderung beim streckreduzierwalzen nebst walzwerk

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3074300A (en) * 1959-04-20 1963-01-22 Beloit Iron Works Automatic control and drive for mills
US3766761A (en) * 1971-10-07 1973-10-23 Wean United Inc Rolling mill control
US3874211A (en) * 1973-03-02 1975-04-01 Sumitomo Metal Ind Method of controlling the wall thickness within a tube elongater by utilizing a screw down control
US4086800A (en) * 1973-09-24 1978-05-02 Friedrich Kocks Gmbh & Co. Process and rolling mill for stretch reduction of tubes
US4002048A (en) * 1975-12-19 1977-01-11 Aetna-Standard Engineering Company Method of stretch reducing of tubular stock

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4415976A (en) * 1981-04-28 1983-11-15 Westinghouse Electric Corp. Method and apparatus for automatic mill zero correction for strip width
US4557126A (en) * 1981-09-30 1985-12-10 Mitsubishi Denki Kabushiki Kaisha Control device for continuous rolling machine
US5086399A (en) * 1988-09-20 1992-02-04 Kabushiki Kaisha Toshiba Method and apparatus for setting-up rolling mill roll gaps
US5485386A (en) * 1990-12-12 1996-01-16 Andreasson; Bengt Method and device for the control and regulation of the stretch of a running web
US20200391263A1 (en) * 2017-11-21 2020-12-17 Sms Group Gmbh Device for controlling a stretch-reducing mill
US11602779B2 (en) * 2017-11-21 2023-03-14 Sms Group Gmbh Device for controlling a stretch-reducing mill
US11745235B2 (en) 2018-08-20 2023-09-05 Sms Group Gmbh Method and device for controlling a stretch reducing rolling mill for wall thickness compensation
CN112823064A (zh) * 2018-10-11 2021-05-18 Sms集团有限公司 管件张力减径时的壁厚控制
US11648597B2 (en) 2018-10-11 2023-05-16 Sms Group Gmbh Wall thickness monitoring while stretch-reducing tubes

Also Published As

Publication number Publication date
FR2469963A1 (fr) 1981-05-29
DE2947233C2 (de) 1992-03-12
IT8049525A0 (it) 1980-08-19
DE2947233A1 (de) 1981-05-27
CS229637B2 (en) 1984-06-18
AT363433B (de) 1981-08-10
GB2070806B (en) 1983-09-01
GB2070806A (en) 1981-09-09
JPS641210B2 (enrdf_load_stackoverflow) 1989-01-10
FR2469963B1 (fr) 1985-07-12
HU182228B (en) 1983-12-28
IT1148248B (it) 1986-11-26
ES486860A1 (es) 1980-06-16
ATA753679A (de) 1981-01-15
JPS5674309A (en) 1981-06-19

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